Chaetonotus (Hystricochaetonotus) slavicus, Križanová & Vďačný, 2022

Križanová, Františka Rataj & Vďačný, Peter, 2022, A huge undescribed diversity of the subgenus Hystricochaetonotus (Gastrotricha, Chaetonotidae, Chaetonotus) in Central Europe, European Journal of Taxonomy 840, pp. 1-93 : 70-71

Chaetonotus (Hystricochaetonotus) slavicus sp. nov.

urn:lsid:zoobank.org:act:9826403E-1298-4889-8E0B-3A19A9EFB3AE

Fig. 9

Molecular diagnosis

18S rRNA gene: 1548 A. ITS2: 52 G, 107 C, 115 A, 156 C, 171 A. Cytochrome c oxidase subunit I (codon ordinal numbers are followed by the corresponding span of nucleotide positions in parentheses): 9 (25‒27) TTC, 65 (193‒195) TTC, 96 (286‒288) CTG, 100 (298‒300) CTG, 143 (427‒429) TCC, 161 (481‒483) GCC.

Reference molecules are shown in Supp. file 1: Figs S8 , S 12B, S 20 . All diagnostic molecular autapomorphies are marked by arrows. Reference alignments with corresponding nucleotide positions are in Supp. file 1: Alignments 1‒4.

The p- distance from species described in the present study is 0.05‒4.38% in 18S, 5.88‒31.02% in ITS2, 0.52‒9.78% in 28S, and 7.85‒13.59% in COI. There are 1‒16 CBCs (except for Ch. (H). arcanus sp. nov., Ch. (H). iratus sp. nov., and Ch. (H). luxus sp. nov., where there are no CBCs) in the 18S rRNA molecule, 1‒3 CBCs in the ITS2 molecule (except for Ch. (H). arcanus sp. nov., Ch. (H). gulosus sp. nov., and Ch. (H). luxus sp. nov., where there are no CBCs), and 2‒18 CBCs in the first two domains of the 28S rRNA gene (except for Ch. (H). arcanus sp. nov., Ch. (H). iratus sp. nov., and Ch. (H). luxus sp. nov., where there are no CBCs).

Etymology

The Latin adjective ‘ slavic · us, - a, - um ’ [m, f, n] (‘Slavic’) refers to the type locality (Devín castle) of the new species, which is an important place in Slovak history.

Material examined

Holotype SLOVAKIA • adult (the specimen was destroyed during DNA extraction); temporary pond in the floodplain area of the River Morava, Devín , Bratislava, Podunajská rovina plain; 48°10′29.4″ N, 16°58′35.8″ E.

Paratypes SLOVAKIA • 3 adults (the specimens were destroyed during DNA extraction); same collection data as for holotype .

Photomicrographs of the holotype are available at the Department of Zoology, Comenius University in Bratislava at https://fns.uniba.sk/en/gastrotricha/.

Type material

A DNA sample of the holotype specimen DB 40 has been deposited in the Natural History Museum, Vajanského nábrežie 2, 810 06 Bratislava, Slovakia (ID Collection Code 01427570).

Type locality

Ephemeral pond in the floodplain area of the River Morava near the foothill of the Devín castle, Bratislava, Podunajská rovina plain, Slovakia, 48°10′29.4″N 16°58′35.8″E.

Gene sequences

The nuclear 18S and ITS 1-5.8S-ITS2-28S rDNA sequences as well as the mitochondrial COI sequence of the holotype specimen DB 40 have been deposited in GenBank under the following accession numbers: OM 421724 , OM 421700 , and OM 424079 , respectively.

Remarks

Unfortunately, all our attempts for thorough morphological investigations of this species failed. Without a name, Ch. (H.) slavicus sp. nov. would be nothing but a label and nucleotide sequences in the GenBank database. However, this entity can be clearly separated from other species by the combination of 18S, ITS region, 28S, and COI sequences. Moreover, it represents a distinct lineage in multi-gene phylogenies ( Fig. 9 ). As ICZN (1999) allows that any part of an animal is eligible to be a name-bearing type (Article 72.5.1), we interpret the isolated DNA as a part of an animal and use it as type material. This strategy is also used in protists whose names are governed by the Zoological Code (e.g., Lynn et al. 2018; Pecina & Vďačný 2022). It is important to mention that the principle of priority applies even if any part of an animal is named before the whole animal (Article 23.3.2.1).

Figures

Fig. 9. Phylogenetic subtree based on 18S, 28S, and COI, showing the systematic positions of the nine new species within the Chaetonotus (Hystricochaetonotus) cluster. Arrows mark the same node in the subtree and the inset phylogram. The whole tree is presented in Fig. 8. The Chaetonotus (Hystricochaetonotus) cluster is highlighted in the inset phylogram. ML bootstrap values and posterior probabilities were mapped onto the best ML tree.

Fig. 8. Phylogenetic tree based on 18S, 28S, and COI sequences, showing the systematic positions of the Chaetonotus (Hystricochaetonotus) cluster (arrow). This clade is collapsed in the three, highlighted in the inset phylogram, and presented in detail in Fig. 9. ML bootstrap values and posterior probabilities were mapped onto the best ML tree.

Fig. 12. Chaetonotus (Hystricochaetonotus) mirabilis sp. nov., holotype (CU-FNS-11-09-19/HO), differential interference contrast. A‒B. Optical sections showing the general body organization. C. Lateral overview. Arrows in (B) and (C) mark the lateral denticle of spines. Scale bars = 30 µm.

Fig. 20. Chaetonotus (Hystricochaetonotus) optabilis sp. nov., differential interference contrast.A. Paratype (CU-FNS-05-03-20-3/PA-2). B–C. Holotype (CU-FNS-05-03-20-1/HO). A. Overview showing the general body organization. Asterisks mark the beginning of the ventral ciliary bands. B‒C. Surface views, showing the head and trunk scale patterns. Scale bars: A = 30 µm; B = 5 µm; C = 10 µm.